Setting a Mac's default email client

I mostly love using Macs, but sometimes the conviences provided are not. I needed to change my default mail client to Microsoft Outlook. You set the default mail client within Apple's Mail app's Settings. However, you can't access Settings unless you first configure an email account! Since I don't want Mail to touch a actual real email account I ran these mail services locally using Docker:

docker run virtuasa/docker-mail-devel
This enabled me to configure Mail to use "debug@example.com" and the local POP server. And now I can access Mail's Settings to set the default mail client to Microsoft Outlook. I really do feel for all those users without there own System Admin.